Keyed thread engagement for filter element

ABSTRACT

A filter element includes a ring of filtration media circumscribing a central axis and defining a central cavity. An annular end cap of the filter element is sealingly bonded at an end of the media. The end cap includes a central opening into the central cavity, and a lateral opening spaced laterally outward from the central opening. The central opening includes a threaded connection portion to enable the element to be spun-on to a complimentarily-threaded connection portion of a filter head. The connection portion of the central opening includes at least one axially-extending slot opening radially away from the connection portion.

FIELD OF INVENTION

The present invention relates generally to filter cartridges, and moreparticularly to spin-on filter cartridges.

BACKGROUND

Filter cartridges are designed to remove contaminants from variousfluids including fuel, engine oil, transmission oil, lubricating oil, orhydraulic oil. In a fuel-delivery system, for example, a filtercartridge filters the fuel upstream of the engine to avoid the illeffects of water and/or contamination. Oil filters are used in manydifferent types of hydraulic machinery, various other vehicle hydraulicsystems, internal-combustion engines, and gas turbine engines. An oftenpreferred filter construction incorporates a “spin-on” filter cartridgethat can be easily installed in tight spaces (e.g., a crowded enginecompartment). With spin-on installation, connections are made, and sealsare formed, by the simple act of spinning the filter cartridge onto athreaded mounting stud.

SUMMARY OF INVENTION

It can be important to provide the correct filter type in eachapplication, and, therefore, presented is a filter head andcorresponding filter cartridge that can prevent the wrong filter frombeing spun-on by providing a keyed fit. One or more studs positioned infront of threads on the filter head can fit in corresponding slots orgrooves in the threading of the filter element. Once pushed past thestuds, the filter element can be spun-on as usual. Further, such asystem can prevent accidental filter drops if the threads are “missed”during a first turn or after threads are disengaged during filterremoval. If the threads are not engaged and the installer drops thefilter element, the filter element may still be held on the filter headbecause the threading on the filter element will be caught by the studson the filter head that are no longer aligned with the slots of thefilter element. Finally, this system can be used to align the threads ofthe filter element with the threads of the filter head by determiningtheir initial relative positions based on the positions of the studs andslots, thus easing installation of the filter element.

Therefore, according to one aspect of the invention, a filter elementincludes a ring of filtration media circumscribing a central axis anddefining a central cavity; and an annular end cap sealingly bonded at anend of the media, the end cap including a central opening into thecentral cavity, and a lateral opening spaced laterally outward from thecentral opening, the central opening including a threaded connectionportion to enable the element to be spun-on to acomplimentarily-threaded connection portion of a filter head, theconnection portion of the central opening including at least oneaxially-extending slot opening radially away from the connectionportion.

Optionally, the at least one axially-extending slot extends from anaxially-outer end of the connection portion to an axially-inner end ofthe connection portion.

Optionally, the at least one axially-extending slot is at least twoaxially-extending slots circumferentially spaced around the connectionportion.

Optionally, the at least two axially-extending slots are equally spaced.

Optionally, the connection portion faces radially inward.

Optionally, the at least one axially-extending slot is as radially deepas a maximum depth of threads on the connection portion.

Optionally, the at least one axially-extending slot extends from anaxially-outer end of the central opening to an axially-inner end of thecentral opening.

Optionally, the at least one axially-extending slot is fouraxially-extending slots circumferentially spaced around the connectionportion.

Optionally, the four axially-extending slots are equally spaced.

Optionally, the at least one axially-extending slot extends in acircumferential direction, thereby forming at least a portion of ahelix.

Optionally, the at least one axially-extending slot includes anaxially-extending portion and a circumferentially extending portion.

Optionally, the at least one axially-extending slot includes a secondaxially-extending portion extending from the circumferentially extendingportion, thereby forming a stepped transition.

According to another aspect of the invention, a filter element includesa ring of filtration media circumscribing a central axis and defining acentral cavity; and an annular end cap sealingly bonded at an end of themedia, the end cap including a central opening into the central cavity,and a lateral opening spaced laterally outward from the central opening,the central opening including a radially-facingcircumferentially-extending first flat portion, and a first threadedportion extending circumferentially from the first flat portion toenable the element to be spun-on to a complimentarily-threaded portionof a filter head.

Optionally, the first flat portion extends from an axially-outer end ofthe first threaded portion to an axially-inner end of the first threadedportion.

Optionally, the filter element further includes a second flat portionextending circumferentially away from a circumferential end of the firstthreaded portion distal the first flat portion, and a second threadedportion extending circumferentially away from a circumferential end ofthe second flat portion distal the first threaded portion.

Optionally, the first and second threaded portions have equalcircumferential extents.

Optionally, the flat portion and threaded portion face radially inward.

Optionally, a maximum thread depth of the threaded portion aligns withthe first flat portion.

Optionally, the first flat portion extends from an axially-outer end ofthe central opening to an axially-inner end of the central opening.

Optionally, the filter element further includes second, third, andfourth flat portions circumferentially spaced around the centralopening, and second, third, and fourth threaded portionscircumferentially spaced around the central opening and respectivelydisposed between respective flat portions.

Optionally, the flat portions are equally spaced.

Optionally, the threaded portions are equally spaced.

Optionally, the at least one axially-extending slot extends in acircumferential direction, thereby forming at least a portion of ahelix.

Optionally, the at least one axially-extending slot includes anaxially-extending portion and a circumferentially extending portion.

Optionally, the at least one axially-extending slot includes a secondaxially-extending portion extending from the circumferentially extendingportion, thereby forming a stepped transition.

According to another aspect of the invention, a filter assembly includesa filter head having an annular threaded connection portion, defining aconnection axis, to enable a filter element having acomplimentarily-threaded connection portion to be spun-on to the filterhead, the connection portion of the filter head including a threadportion and a lock portion axially outward of the thread portion, thelock portion having at least one radially-projecting stud sized so as tointerfere with threads of the complimentarily-threaded connectionportion of the filter element.

According to another aspect of the invention, a filter head adapterincludes an annular body circumscribing a central opening and defining alongitudinal axis, the annular body having a threaded keyed connectionportion to enable the adapter to be spun-on to acomplimentarily-threaded connection portion of a filter head, the keyedconnection portion including at least one axially-extending slot openingradially away from the keyed connection portion, and the annular bodyhaving a threaded filter connection portion to enable acomplimentarily-threaded filter element to be spun-on to the adapter.

Optionally, the keyed connection portion is axially offset from thefilter connection portion.

Optionally, the keyed connection portion is interiorly-threaded.

Optionally, the filter connection portion is exteriorly-threaded.

Optionally, the at least one axially-extending slot extends from anaxially-outer end of the keyed connection portion to an axially-innerend of all threads of the keyed connection portion.

Optionally, the at least one axially-extending slot is at least twoaxially-extending slots circumferentially spaced around the connectionportion.

Optionally, the at least two axially-extending slots are equally spaced.

Optionally, the connection portion faces radially inward.

Optionally, the at least one axially-extending slot is radially deeperthan a maximum depth of threads on the connection portion.

Optionally, the at least one axially-extending slot is fouraxially-extending slots circumferentially spaced around the connectionportion.

Optionally, the four axially-extending slots are equally spaced.

Optionally, the at least one axially-extending slot extends in acircumferential direction, thereby forming at least a portion of ahelix.

Optionally, the at least one axially-extending slot includes anaxially-extending portion and a circumferentially extending portion.

Optionally, the at least one axially-extending slot includes a secondaxially-extending portion extending from the circumferentially extendingportion, thereby forming a stepped transition.

The foregoing and other features of the invention are hereinafterdescribed in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial perspective view of an exemplary filter elementhaving a slotted connection portion;

FIG. 2 shows a top view of an exemplary filter element having a slottedconnection portion;

FIG. 3A shows a partial cross-sectional view of an exemplary filterelement having a slotted connection portion;

FIG. 3B shows a partial cross-sectional view of another exemplary filterelement having a slanted slotted connection portion;

FIG. 3C shows a partial cross-sectional view of another exemplary filterelement having a stepped slotted connection portion;

FIG. 4 shows a partial side view of an exemplary filter head having astudded connection portion;

FIG. 5 shows an exemplary connection portion of a filter element alignedwith a complimentary connection portion;

FIG. 6 shows an exemplary connection portion of a filter element alignedwith and being inserted over a complimentary connection portion;

FIG. 7 shows an exemplary connection portion of a filter element havingbeen spun-on to a complimentary connection portion;

FIG. 8 shows a conventional filter element without slots that cannotaccept the studded connection portion of an exemplary filter head; and

FIG. 9 shows an exemplary adapter for converting an exemplary filterhead into a conventional filter head; and

FIG. 10 shows a cross-section of the exemplary adapter for converting anexemplary filter head into a conventional filter head.

DETAILED DESCRIPTION

In order to ensure the correct filter type is used in each application,to exemplary filter heads can prevent the wrong filter from beingspun-on by providing a keyed fit. One or more studs positioned in frontof threads on the filter head can fit in corresponding slots or groovesin the threading of exemplary filter elements. Once pushed past thestuds, the filter element can be spun-on as usual. Exemplary assembliescan also prevent accidental filter drops if the threads are “missed”during a first turn or after threads are disengaged during filterremoval: if the threads are not engaged and the person installing thefilter element drops it, the filter element may still be held on thefilter head because the threading on the filter element will be caughtby the studs on the filter head. Finally, this system can be used toalign the threads of the filter element with the threads of the filterhead by determining their initial relative positions based on thepositions of the studs and slots, thus easing installation of the filterelement.

Turning to FIGS. 1-3A, an exemplary filter element is shown at 10 in theform of a filter cartridge. The filter element includes a canister 21and an end cap 23 enclosing filtration media 22.

The canister 21 may take the form of a generally cylindrical shell withan open end and an opposite closed end. The canister 21 may beconstructed, for example, of drawn metal (e.g., steel) and/or it can beformed in one-piece. A rim 31 surrounds the canister's open end and itis shaped to receive the end cap 23 which may, for example, be attachedand sealed by a folding operation at the interface between the end capand the canister. Alternative arrangements known in the art are alsopossible.

The filtration media 22 may be any suitable filtration media known inthe art, and is herein depicted as a cylindrical compilation or ring oflongitudinal pleats, for example, and may circumscribe a central axis ofthe filter element and define a central cavity 25. Further, thefiltration media 22 may be spaced from the canister 21 forming an outerchamber 29.

The end cap 23 may be annular and include a central opening 26 into thecentral cavity. The end cap 23 may also include one or more lateralopenings 27 (usually a plurality of equally spaced openings) spacedlaterally outward from the central opening. The exemplary embodimentdepicted herein includes eight such openings 27 equally spaced aroundthe end cap. The laterally outwardly spaced openings 27 may preferablyby inlets to the filter, with the central opening 26 acting as anoutlet. However, the opposite arrangement is also possible. As shown,the outer openings 27 are in fluid communication with the outer chamber29 such that fluid entering the canister would flow into the outerchamber 29, pass through the filtration media into the central cavity25, and then flow out the central opening 26.

The end cap 23 may include an axially outward facing annular sealingmember 32 which seals the filter element to the filter head after it isspun on.

The central opening 26 includes a threaded connection portion 40 toenable the filter element to be spun-on to a complimentarily-threadedconnection portion 140 of a filter head 110. The connection portion 40of the central opening 26 includes at least one axially-extending slot42 opening radially away from the connection portion. The exemplaryfilter element is depicted as having four such slots 42, but any numberof slots may be used.

The slots are essentially radially-facing circumferentially-extendingflat portions. Threaded portions 48 extend circumferentially from theflat portions to enable the element to be spun-on to acomplimentarily-threaded portion of a filter head. The flat portions or(slots that run through the threads of the connection portion) allow thecomplimentary studs of the connection portion of the filter head toslide past the threads without interfering with the threads. In otherwords, the slots or flat portions act as a key to allow the filterelement to be spun on to a “locked” filter head.

The slots 42 extend axially all the way through the threads of theconnection portion. In exemplary filter elements in which the entireconnection portion is threaded or in which the slots are of a depth thatis different than the thread depth, the slots 42 may extend from anaxially-outer end of the connection portion to an axially-inner end ofthe connection portion. In a situation in which the slots extendradially deeper than the threads, there may also be a circumferentialgroove around the axially inner side of the connection portion in orderto accommodate the studs of the filter head during spinning of thefilter element.

The slots are described as having a “flat” portion. Flat as used hereinis meant to encompass any portion that is recessed so as allow the studto pass through the threads. In particular, such recessed portion or“flat” may be flat in both axial and circumferential directions.Alternatively, this recessed portion may be flat along the axialdirection but include a curved circumferential surface that may have thesame radius of curvature as the central opening, or a different radiusof curvature.

Furthermore, the slots are shown in FIG. 3A as extending in merely anaxial direction (although having a circumferential extent). Turning nowto FIG. 3B, an exemplary embodiment of the filter element is shown at210. The filter 210 is substantially the same as the above-referencedfilter element 10, and consequently the same reference numerals butindexed by 200 are used to denote structures corresponding to similarstructures in the filter element. In addition, the foregoing descriptionof the filter element 10 is equally applicable to the filter element 210except as noted below. Moreover, it will be appreciated upon reading andunderstanding the specification that aspects of the filter elements maybe substituted for one another or used in conjunction with one anotherwhere applicable. In particular, the filter element 210 includes slots242 which are slanted and thus extend in both an axial and acircumferential direction and therefore form at least a portion of ahelix, as shown in FIG. 3B.

Turning now to FIG. 3C, an exemplary embodiment of the filter element isshown at 310. The filter 310 is substantially the same as theabove-referenced filter elements 10 and 210, and consequently the samereference numerals but indexed by 100 are used to denote structurescorresponding to similar structures in the filter element. In addition,the foregoing description of the filter elements 10 and 210 are equallyapplicable to the filter element 310 except as noted below. Moreover, itwill be appreciated upon reading and understanding the specificationthat aspects of the filter elements may be substituted for one anotheror used in conjunction with one another where applicable. Alternativelyor additionally to the slots 42 and 242 described above, the slots 342may include one or more curved or step transitions, as shown in FIG. 3C,in which a portion extending in either a generally axial orcircumferential direction transitions to a portion extending in theopposite direction. Therefore, as shown, slots 342 may include a firstaxially extending portion 343, a first circumferentially extendingportion 345 extending from the first axially extending portion 343, anda second axially extending portion 347 extending from thecircumferentially extending portion 345.

It is also contemplated that exemplary slots may transition fromextending axially outward to extending axially inward beforetransitioning back to an axially outward direction. Such a configurationmight require an exemplary filter to be pushed in, turned, partiallypulled out, turned, and pushed in again before threads may be engaged.These configurations are merely given as examples, and are not meant tobe limiting.

The slots 42, 242, 342 may be circumferentially spaced around theconnection portion in an equally spaced manner as shown, or in anunequally spaced manner. Unequal spacing may provide for a single“correct” orientation when installing the filter element.

Although shown as facing radially inward, the connection portion (andtherefore the threads and the slots) may also face radially outward andmesh with a complimentary connection portion on the filter head.

Referring specifically to FIG. 4, shown is a portion of a filter head at110. The filter head may be any conventional body that accepts spin-onfilters such as, e.g., a portion of a manifold, except with thedifferences described herein. Exemplary filter heads include an annularthreaded connection portion 140 that have a thread portion 142 and alock portion 144. The lock portion 144 extends axially outward (awayfrom the filter head and towards a filter element) from the threadportion and includes one or more studs 146 which project radially awayfrom sidewalls of the lock portion.

As shown in the exemplary embodiment in FIG. 4, the studs may projectradially outward, although they may also project radially inwardinstead. In any case, the studs should be on the same radial side as thethreads of the thread portion.

As shown, the stud 146 profile may include rounded axial corners to easeinsertion into the slots, however, other profiles are possible. Thestuds 146 may have a circumferential curve on its radial end to match acorresponding circumferential curve of the flat surface of the slots.Alternatively, the studs 146 may include a flat radial end. Further,other profiles may be provided as, for example, requested by a customer.Further, the stud may extend in an axial and/or circumferentialdirection, and may extend is a partial or full helical pattern.

Further, any number of studs is possible, with FIG. 4 showing aconfiguration having 4 equally spaced studs. Studs may be disposedequally spaced or unequally spaced. Unequal spacing may provide a singleacceptable orientation of a filter element to be spun-on to the filterhead.

The stud(s) 146 should project sufficiently far so as to provideinterference to threads on a complimentary filter element. Therefore, inexemplary embodiments, the stud 146 projects as far or farther than themaximum radial extent of the threads of the thread portion 142.

Exemplary connection portions 110 include a central opening 150 and oneor more lateral openings (not shown) which fluidly communicate with therespective openings of an attached filter element.

Turning now to FIGS. 5-7, shown are a sequence of images showing theattachment of an exemplary filter element to an exemplary filter head.

FIG. 5 shows an exemplary connection portion 40 of a filter elementaligned with a complimentary connection portion 140.

FIG. 6 shows an exemplary connection portion 40 of a filter elementaligned with and being inserted over a complimentary connection portion140. In particular, the studs 146 are being inserted through the slots42.

FIG. 7 shows an exemplary connection portion 40 of a filter elementhaving been spun-on to a complimentary connection portion 140. In otherwords, the filter element is now threadably engaged with the filterhead—the studs 146 having passed through the slots 42 and the respectivethread portions being intermeshed with each other after being rotatedrelative to each other in the engaging (e.g., clockwise) direction afterinitial thread alignment.

FIG. 8 shows a conventional filter element without slots 42 that cannotaccept the studded connection portion of an exemplary filter head.

Referring now to FIGS. 9 and 10, shown is an exemplary filter headadapter 410 which may be provided to allow a conventional filter to beattached to an exemplary filter head. This adapter 410 includes a keyedconnecting portion 440 with any of the characteristics described abovewith respect to the connection portions of exemplary filter elements. Inparticular, a keyed connection portion 440 enables the filter adapter tobe spun-on to a complimentarily-threaded connection portion 140 of afilter head 110. The connection portion 440 of the adapter 410 includesat least one axially-extending slot 442 opening radially away from theconnection portion.

Further, the adapter 410 includes a threaded filter connection portion480 configured to allow a conventional filter to be spun-on to thefilter adapter, and thus the filter head.

The exemplary filter connection portion 480 is shown as being axiallyoffset from the keyed connection portion 440, although this need not betrue, for example, in cases in which the filter to be spun-on is of adifferent size than the corresponding filter head connection. Further,the exemplary filter connection portion 480 is shown to beexteriorly-threaded while the keyed connection portion 440 is shown tobe interiorly threaded, however, they may be switched, or bothinteriorly-threaded or both exteriorly-threaded, depending on theconnection desired.

Although the invention has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodimentsof the invention. In addition, while a particular feature of theinvention may have been described above with respect to only one or moreof several illustrated embodiments, such feature may be combined withone or more other features of the other embodiments, as may be desiredand advantageous for any given or particular application.

What is claimed is:
 1. A filter element, comprising: a ring offiltration media circumscribing a central axis and defining a centralcavity; and an annular end cap sealingly bonded at an end of the media,the end cap including a central opening into the central cavity, and alateral opening spaced laterally outward from the central opening, thecentral opening including a first, threaded connection portion to enablethe element to be threadably connected to a complimentarily-threadedconnection portion of a filter component, the first connection portionof the central opening including at least one angled slot extending atan angle offset from the central axis, and opening radially away fromthe first connection portion.
 2. The filter element of claim 1, whereinthe at least one angled slot extends from an axially-outer end of thefirst connection portion to an axially-inner end of the first connectionportion.
 3. The filter element of claim 1, wherein the at least oneangled slot is at least two angled slots circumferentially spaced aroundthe first connection portion.
 4. The filter element of claim 1, whereinthe first connection portion faces radially inward.
 5. The filterelement of claim 1, wherein the at least one angled slot is as radiallydeep as a maximum depth of threads on the first connection portion. 6.The filter element of claim 1, wherein the first threaded connectionportion defines the central opening, and the at least one angled slotextends from an axially-outer end of the central opening to anaxially-inner end of the central opening.
 7. The filter element as inclaim 1, wherein the at least one angled slot extends through thethreads of the first connection portion.
 8. A filter element,comprising: a ring of filtration media circumscribing a central axis anddefining a central cavity; and an annular end cap sealingly bonded at anend of the media, the end cap including a central opening into thecentral cavity, and a lateral opening spaced laterally outward from thecentral opening, the central opening including a first, threadedconnection portion to enable the element to be threadably connected to acomplimentarily-threaded connection portion of a filter component, thefirst connection portion of the central opening including at least oneangled slot opening radially away from the first connection portion,wherein the at least one angled slot forms at least a portion of ahelix.
 9. A filter assembly comprising: i) a filter component having anannular connection portion defining a connection axis, and ii) thefilter element of claim 8, the first connection portion of the filtercomponent including a threaded portion having complimentary threads tothe first threaded connection portion of the central opening, and a lockportion axially outward of the threaded portion, the lock portion havingat least one radially-projecting device sized so as to be receivedwithin at least one angled slot opening of the first connection portion,when the filter element is threadably connected to the filter head.